The Armour39 system includes a strap, a bug, and an optional watch accessory. Data can be read on the Web or off a free iOS app.
Roger Cheng/CNET

Under Armour is prepared to jump into the heavily contested field of fitness monitoring with its Armour39 system.

Armour39 consists of a sensor-equipped strap worn around the chest (or right below it); it includes a center sleeve for a "bug," which acts as a computer in storing and moving fitness data to the cloud via Bluetooth. Users can check their progress on a watch or by way of an app on the smartphone. The system will be available on March 20. The strap and bug will cost $149.99, while the optional watch accessory will cost $199.99.

In moving into this field, the sports apparel manufacturer will take on large companies such as Nike and its FuelBand, as well as established fitness monitoring players such as FitBit and JawBone.

The market for fitness-monitoring devices has exploded during the past year or so with a number of companies linking small motion sensors to smartphones and Web sites, allowing users to get a more complete picture of their workout regimen and progress. Companies also have added a social element, allowing people to compete and share their workout stats.

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With Apple potentially getting into the business with the rumored iWatch, some believe the already growing market may take off even further in the coming months.

Armour39, which is named for 0039, the style number for Under Armour's first white undershirt, measures heart rate, calories burned, and intensity, and comes up with a combined score that Under Armour calls "WILLpower," which is rated on a scale between 1 and 10.

At first glance, WILLpower sounds a lot like Nike's own proprietary Nike Fuel score, which is its own measurement of activity. But Under Armour CEO Kevin Plank said the Willpower score quantifies how hard and intense the session can be.

For some of these companies, including Nike and Under Armour, these devices represent a marked departure from their core business. Neither are known as hardware companies, and Nike has had to prove itself with the FuelBand, which generally got strong reviews for its design and features.

Of course, Under Armour itself shot up from seemingly nowhere. The company, founded in 1996, was a fledgling maker of fitness clothing and now stands alongside brands such as Nike and Reebok in the sports world, and is easily visibly at events such as the Olympics and in National Football League games.

Armour39 was part of a larger presentation by Under Armour, which also unveiled the launch of a massive "brand house" in Baltimore, a new "I will" campaign, new cold wear, as well as the tease for a new shoe that won't be manufactured in a factory, but will "clothe your feet."

While Under Armour has a lot of momentum behind it, the company still has an uphill climb in its attempt to breach the already crowded fitness-monitoring market.

About the author

Roger Cheng is the executive editor in charge of breaking news for CNET News. Prior to this, he was on the telecommunications beat and wrote for Dow Jones Newswires and The Wall Street Journal for nearly a decade. He's a devoted Trojan alum and Los Angeles Lakers fan.
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